Sirolimus improves early microcirculation, but impairs regeneration after pancreatic ischemia-reperfusion injury.

Ischemia and reperfusion injury remains a relevant problem in clinical pancreas transplantation. We investigated the effect of sirolimus (SRL) in a rodent model of 90-min warm pancreatic ischemia. Four groups were studied: (1) sham surgery and vehicle; (2) sham surgery and SRL; (3) warm ischemia and vehicle; (4) warm ischemia and SRL.

Quantification of basal and stimulated ROS levels as predictors of islet potency and function.

We have developed a luminol-based assay using intact islets, which allows for quantification of reactive oxygen species (ROS). In addition, an index capable of characterizing metabolic and mitochondrial integrity prior to transplantation was created based on the capacity of islets to respond to high glucose and rotenone (mitochondrial respiratory chain complex I inhibitor) by production of ROS. To validate this assay, lipid peroxidation and antioxidative defense capacity were evaluated by detection of malondialdehyde (MDA) levels and glutathione peroxidase activity (GPx), respectively.

Attenuation of proinflammatory gene expression and microcirculatory disturbances by endothelin A receptor blockade after orthotopic liver transplantation in pigs.

Background: Endothelin-1 (ET-1), a very potent mediator of vasoconstriction, leads to microcirculatory disturbances and release of proinflammatory cytokines under pathophysiologic conditions. Our aim was to evaluate the effect of a selective ET(A)-receptor antagonist (ET(A)-RA) on cold ischemia/reperfusion (I/R) injury in a pig model.

Methods: Twenty pigs revealed orthotopic liver transplantation.

Validation of large particle flow cytometry for the analysis and sorting of intact pancreatic islets.

Background: Accurate quantification of total islet yield is an essential step prior to transplantation and for research. The standard method of manually determining an islet equivalent (IEQ) count is subjective and prone to error. We evaluated Complex Object Parametric Analyzer and Sorter (COPAS) large particle flow cytometry for the determination of islet equivalent counts and purities of islet preparations.

Effects of ET(A) receptor antagonism on proinflammatory gene expression and microcirculation following hepatic ischemia/reperfusion.

Background: The objective of this study was to investigate the effect of a specific endothelin(A) receptor antagonist (ET(A)-RA) on mRNA expression of genes encoding vasoactive mediators and proinflammatory cytokines and on the microhemodynamics (assessed by measurement of laser Doppler flow and tissue blood gases) following complete vascular exclusion of the porcine liver.

Study Design: Sixteen adult German landrace pigs were subjected to 120 min of warm hepatic ischemia by total vascular exclusion. To avoid portal congestion, a passive porto-femoro/jugular bypass was implanted.